Most of the 1.34 million subscribers on China Mobile's nascent 4G TD-LTE network are using iPhones, the company said on Thursday, but investors hoping for a more detailed breakdown will be left disappointed as the carrier declined to elaborate further.

"We added 1.34 million new 4G users in February and most of them are iPhone users," China Mobile chairman Xi Gouhua said in an interview with the Wall Street Journal. February was the first full month in which the iPhone was officially available on China Mobile, the world's largest wireless carrier.

While many have pointed to that figure as a representation of the iPhone's overall sales performance since the handset's debut on China Mobile, it may not tell the whole story.

Customers outside of the carrier's 4G footprint —which covers fewer than 20 of the more than 160 cities in China with over 1 million inhabitants —must either purchase the device outright or with a 3G contract. China Mobile added 14 million 3G customers in January and 10 million in February.

iPhones compatible with China Mobile's network are also sold without a contract at Apple retail stores and third-party outlets throughout the mainland and Hong Kong. Many Chinese consumers, especially those from the populous and geographically adjacent Guangdong province, travel to Hong Kong to purchase electronics thanks to the semiautonomous region's favorable tax rates, which can result in a savings of more than $100.

If the 4G numbers do represent the bulk of Apple's iPhone sales on China Mobile, they would fall short of analyst expectations that ran as high as 5 million units per quarter. There are already as many as 30 million previous-generation iPhones on China Mobile's network, however, and sales numbers are likely to increase as those subscribers reach their next upgrade cycle.